Behind the waterfall (idea)

In the world of video games, a waterfall is a dead giveaway for secret passages and secret goodies. Any time you are walking around an area and you see a waterfall, there is a 81.4% chance that there is a secret behind it. What type of secret lies on the other side of the falling waterfall depends on the type of video game we are talking about:

Most likely an alcove or passage leading to extra life/ammo/weapons. The only examples I can think of are Duke Nukem 3D, and Serious Sam, which leades to health. (Oh yeah, Daikatana too, but I never bought that game, I swear!)

Probably not as common, but some racing games hide shortcuts behind waterfalls. Mario Kart 64 has a waterfall shortcut which requires a highly technical maneuver involving obtaining speed mushrooms (!) and using them in unison with a jump ramp. Failure to execute perfectly results in a significant loss of time. If my memory serves my right, Jet Moto has a waterfall secret as well.